struggling with low light exposures.

i don't understand how photographers possibly shoot in low lighting based on my meter readings. even when i'm metering for my highlights (in the last photo) at 800 speed, the readings are at a shallow aperture and a slow shutter speed. I want to still have details in my shadows without them being completely crushed. & i honestly don't want my key light to be this bright or harsh, but it's hard to get a usable reading when i add diffusion or dim the light. someone please help me understand.

My Equipment mamiya rb67, 50mm, 4.5 sekonic handheld light meter. arri 650 fresnel arri 300 fresnel

I'm going to use a roll to bracket my exposures but i just want to have a solid understand before i do.